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3 years ago

PLZ HELP

Mathematics

1 answer:

borishaifa [10]3 years ago

4 0

The two equations are

P: y+z =6 and

Q: 5y +9z =1

Now to eliminate y , we have to make the coefficient of y same and with opposite sign

In equation Q , the coefficient of y is 5

So in equation P the coefficient of y should be -5

So we multiply equation P by -5

So (y + z = 6) ⋅ −5

Option second is correct

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There is approximately 0.26 gallon in 1 liter. Determine how many liters are in 520 gallons

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Multiply 0.26 by 520 to get 135.2 gallons

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3 years ago

Find the volume of a pyramid with a square base, where the perimeter of the base is

dalvyx [7]

Answer:

12.5

Step-by-step explanation:

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3 years ago

Solve using identities [0,2) cos2x=sinx

bekas [8.4K]

We have:

$\cos 2x = 1 - 2 \sin^2 x$

Thus:

$1 - 2 \sin^2 x = \sin x$

Adding $2 \sin^2 x - 1$ gives:

$2 \sin^2 x + \sin x - 1 = 0$

Factoring gives:

$(2 \sin x + 1)(\sin x - 1) = 0$

Thus, we have:

$\sin x = \frac{-1}{2}$

or

$\sin x = 1$ .

Note that because $2 \pi > 2$ , there will be no solutions $y$ of the form $2n\pi + z$ for positive integer $n$ and solution $z$ . So we find the basic values of $x$ giving $\sin x \in (\frac{-1}{2}, 1)$ .

For $\sin x = \frac{-1}{2}$ with positive $x$ , $x > \pi > 2$ (this can be seen easily from the unit circle. But $x < 2$ , a contradiction. So we examine the case in which $\sin x = 1$ .

In this case, $x = \frac{\pi}{2}$ . So this is the only solution to this equation.

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3 years ago

The vertex form of the equation of a parabola is y = (x + 5)2 + 49.

krok68 [10]

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4 years ago

Can someone help me with 13,14,15 and 16 please

xeze [42]

Answer: -3/5, 18/32, -10/11, and horizontal.

Step-by-step explanation: Remember the equation for slope? Δy (the change in y), over Δx (the change in x). In other words, rise over run. To solve for Δ, you'd have to subtract the second output (y²) from the first (y¹). There are really no rules as to which has to be minuend and the subtrahend, so I chose to subtract (-1,6) from (4,3) for the first problem.

y¹-y² Δy 3-6 -3

------ or ---- so ------- = ----- The slope is represented by -3/5x

x¹-x² Δx 4-(-1) 5

__________________________________________________________

For the second, substitute the values again (make sure you keep the xs and ys together and in the right order, otherwise your answer will be incorrect). Remember that subtracting a negative number is basically just adding a positive number. That's why the slope is 18/32 and not 4/26.

11-(-7) 18

--------- = -------

29-(-3) 32

___________________________________________________________

For number three, they give you a point, then tell you the y-intercept. With that in mind, also know the second point is (0,17), because the x value at the y-intercept is always 0.

7-17 -10

------ = ------- The slope is -10/11x

11-0 11

___________________________________________________________

4-4 0

------ = --------

6-(-9) 15

Because there is no Δy, but there is Δx, we know that the line for y will be straight and shows no change- it will always be at 4. That said, the line will be horizontal.

I hope this helps. I know this is very confusing at first, but with practice, you'll eventually get the hang of it. I've tried to explain the rules to the best of my ability- let me know if there's anything you don't understand or need more help with.

Sincerely,

Lacia :))

5 0

3 years ago